Machine for making circular lathe brushes



Nov. 19, 1946. J. HALL 2,411,265

MACHINE FOR MAKING CIRCULAR LATHE BRUSHES Filed May 15, 1943 2 Sheets-Sheet l NOV. 19, 1946. J, HALL 2,411,265

MACHINE FOR MAKING CIRCULAR LATHE BRUSHES Filed May 15, 1943 2 Sheets-Sheet 2 Patented Nov. 19, 1946 MACHINE FOR MAKING CIRCULAR LATHE BRUSHES James Hall, Leeds, England, assignor to Kingswood Manufacturing Co. Limited, Letchworth, Herts, England, a company of Great Britain Application May 15, 1943, Serial No. 487,173 In Great Britain May 26, 1942 7 Claims. 1

This invention relates to machines for making circular lathe brushes, especially circular dental lathe brushes, with rows of converging bristles, i. e. machines which drill the brush stocks and/or fill drilled stocks with bristles, Brushes of this type comprise a cylindrical wooden stock which is drilled all around its cylindrical face with two or more rows of holes, staggered in relation to one another and running parallel with the side faces of the stock, into which bristles are inserted. The brush in use is rotated at high speed for buffing dental plates or the like.

The main object of this invention is to improve the machine stock holders and their control devices, that is, each stock holder is pivoted to allow a stock to be tilted or inclined for changing its position so that different rows of holes can be drilled at the correct angle and a supporting cam track is furnished for enabling such movement and angle of presentation to be effected at will by a single operative movement. This arrangement is equally applicable to the stock holder which supports a drilled stock during the bristle insertion operation. Furthermore the stock holders may be duplicated with a common control device on a combined drilling and bristle inserting machine.

Another object is to advance automatically, during the tilting movement of the stock holder, the means which rotate the stock, so that the holes of a subsequent row will be staggered in relation to the holes in the previous row.

Referring now to the accompanying drawings, an embodiment of the invention is shown by way of example and will be described as applied to a combined drilling bristle inserting machine, wherein a pair of stock holders are adapted to be advanced towards and away from the drill and bristle inserting means.

Fig. .l is a part sectional side elevation showing one of the stock holders and the control means;

Fig. 2 is a sectional side elevation of a stock holder;

Fig. 3 is a plan view showing the general arrangement of the stock holders and mechanism;

Fig. 4 is a plan view, from beneath, of the mechanism for rotating brush stocks, and

Fig. 5 is a fragmentar view, partly in section, oi the cam track and associated member for imparting a step-by-step angular adjustment to the stock holders.

A pair of stock holders l are pivoted at their front ends by pins 2 to a pair of bifurcated carrier heads3 arranged on the machine behind, and in alignment with, the drilling and bristle inserting means 4, 5. Each of the stock holders comprises a pair of side arms and a rear part with a web between the arms carrying a rotatable stock receiving pin 5. The forward ends of the arms have resilient buffer means 1 associated with the pivot pins 2 which support the holder and the back face of the rear part has a cam face 8 working against the rounded front endof the operating arm 9. In this manner a stock holder i can be moved about its pivots 2 with a stock iii thereon and an even depth of hole will be maintained in the different rows in relation to the straight stock face being tilted. The general construction and arrangement of the machine parts for operating the stock holders towards and away from the means i and 5 are of known type and the only members shown are the arms 6 (which are tied together and slide horizontally in the machine frame) to which the carrier heads 3 are secured. The arms are reciprocated'tin bearings by a rocking lever in known manner.

The device for tilting the stock holders I about their pivots 2 after the first simultaneous drilling and filling operations, comprises a stepped cam track it which acts as a support for the rear of the holders, The latter are tied together by a cross bar 52 with a pendant arm is intermediate its ends having a roller i i (in two parts) at its lower end working in a slot Ma formed in a horizontal member 65. lhe roller is divided at its center (for mountin purposes) with end flanges t c-b, i. e. lik a transversely split bobbin. In this manner although the member i5 is secured to the top of a vertical cam rod is which rests on the stepped cam track ii and is supported freely in a stationary boss ll (fixed to the machine frame) to have a rising and falling motion under the control of the cam track, the flanges Mb maintain the relative positions of the roller I l and the guide member !5.' Also, the member 15, which is merely the supporting link between the arm is and the cam rod I6, is slotted because the arm is has a horizontal reciprocatory movement with the stock holders I whilst the rod [6 has a vertical reciprocatory movement in the fixed boss ll. The cam track i! is extended for wardly in the form of a handle l8 which may be supported by the machine frame and the cam track itself is supported in the boss I! in which the cam rod works. As the handle I3 is pushed in, the cam rod l6 slips from the top step of the cam track itself down an incline to the next step so that the horizontal slotted member 15, the pendant arm !3 and the cross bar l2 all fall causing the stock holders l to tilt downwardly about their pivots 2. The stocks ID are now at the correct level and angle in relation to the drilling and filling means 4, 5, for a second row of holes to be drilled and filled, The cam track can again be operated for a further row (or rows) of holes and is stepped to correspond with the number of rows of holes it is desired to drill and fill. To retain the cam track in each adjusted position, the handle it is notched to receive a spring actuated lever l9.

To afford adjustment for varying the number of rows of holes in a stock, difierent sizes of spacing collars Fill may be inserted between the cross bar i2 and pendant arm is to pivotally lift or lower the stock holders with respect to the stepped cam track and so centralize the stocks with the drill and filling means. Other adjusting means may be employed. Make-up washers 2! are also used on the stock receiving pins 5 for the stocks to rest on so as to allow for diilerent widths of stocks and a top and bottom clamping washer 22 grips each stock. To support Or brace each of the pins 6 against the pressure of the drilling and bristle inserting means 4, 5, a pivoted plate 23 has its bifurcated outer end dropped on to the upper stock clamping washer 22 before the nut 25! is located on the pin.

To enable the distance between the rows of holes to be adjusted, the head of the aforesaid pendant arm i3 is secured in a transverse slot 12a in the cross bar I 2 so that the effective radial distance between the roller M and the stock holder pivots 2 may be varied at will by moving the arm l3 in said slot slightly nearer to or further from said pivots for adjusting the actual arcuate movement of the stock holders.

The stock receiving pins t are rotated by ratchet wheels 25, which are operated by pawls 26 carried by brackets 21, mounted freely on the bosses of the ratchet wheels, linked together by a cross rod 28 and a trip member 2% engaging a stationary roller 36 each time the bifurcated heads 3 are retracted by the machine mechanism (not shown) to a normal position. The arrangement is to advance the ratchet wheels 25 tWo teeth each time during the operations on any one row of holes, and to start the next row (having a similar spacing for the holes) after advancing the ratchet wheels only one tooth during the change from the'last hole of one row to the first hole of the next row.

' holes in adjacent circumferential rows are thereby, staggered, and the falling movement of. the stock holders I is arranged automatically to rotate the stocks it] the required amount. As the stepped cam track ll lowers the stock holders, a member 3! secured on the cross link rod 28 of the pawls 26 bears down on to the nearest one of a series of fixed pins 32 (whose free ends are chamfered off to form downwardly inclined cam tracks), so that as the rod 28 is capable of axial movement against the action of its return spring 33 (anchored to the adjacent stock holder I) the member 3! slips laterally and downwardly off the pin 32, causes the rod 28 to move axially which through the pawls 26 advances the ratchet wheels 25 one tooth and so staggers the holes in the next row, As the memher 3! slips off the pin 32 (carrying the rod 28 with it) itis immediately pulled back above the next pin 32 by its return spring. A locking pawl its for each wheel 25 ensures correct engagement between the operating pawls and the ratchet wheels. 1

To raise the stock holders to a normal position the pawls 26 are released temporarily by manual operation of the trip member 29 and the cross bar l2 pulled up by means of, say, a handle 35 when the stepped cam track 3! can be pulled forwardly its full extent.

It is to be understood the invention may be applied to separate drilling and filling machines and that it can be modified in a variety of ways without departing fromthe scope thereof,

What I claim is:

1. In a machine for making cylindrical brushes of the dental lathe type, a stock holder, a pin rotatably supported on said stock holder for receiving a cylindrical brush stock, a carrier head having pivot means supporting the forward end of said stock holder for angular movement to present the stock to work devices so that different rows of holes may be drilled or filled with bristles at the correct angle, means supporting said carrier head for reciprocatory movement with respect to said work devices, and means connected to the rear end of said stock holder to support the stock holder for reciprocation with said carrier head, said supporting means being adjustable vertically to effect the desired changes in the angular presentation of the cylindrical brush stock.

2. In a machine for making cylindrical brushes of the dental lathe type, the invention as recited in claim I, wherein said supporting means includes a cam rod engaging a stepped cam track, a horizontally slotted member secured to said rod, an arm secured to the rear portion of said stock holder, and a roller carried by said arm and cooperating with said slotted member to support the rear end of the stock holder for reciprocatory movement.

3. In a machine for making cylindrical brushes of the dental lathe type, the invention as recited in claim 1 wherein said supporting means includes a cam track, a cam engaging device having a horizontal slot at its upper end, an arm secured to the rear end of said stock holder and carrying means cooperating with said slotted device to uide said stock holder during reciprocatory movement thereof. e

i. In a machine for making cylindrical brushes of the dental lathe type, the invention as recited in claim 1 wherein said supporting means includes a cam track and means automatically locking the same in each adjusted position.

5. In a machine for making brushes, a stock holder including a rotatable pin on which a cylindrical brush stock may be secured, pawl and ratchet. means for imparting angula movement to said pin, a reciprocatory carrier having pivot means mounting said stock holder for tilting movement about an axis normal to the axis of said pin, means including a cam track and cam rod for imparting a step-by-step tilting movement to said stock holder, and means actuated by said stock holder during movement thereof to operate said pawl and ratchet means to impart a step advance to said pin. 7

6. In a machine for making brushes, a stock holder including a rotatable pinon which a cylindrical brush stock may be secured, pawland ratchet means for imparting angular movement to said pin, a reciprocator carrier having pivot means mounting said stock holder for tilting movement about a horizontal axis normal to the axis of said pin, supporting means adjustably connected to said stock holder at a point spaced from said pivot means, said supporting means including a vertically arranged cam rod extend- 5 ing below said stock holder and resting upon a cam track, whereby displacement of the cam track imparts a tilting movement to said stock holder, and means actuated by the stock holder,

during movement thereof to operate said pawl and ratchet means to impart a step advance to said pin.

'7. In a machine for making brushes, a pair of laterally arranged stock holders pivotally supported on reciprocatory carriers for tilting movement about a horizontal axis, a pin journalled on each stock holder on which a cylindrical brush stock may be secured, a cross bar connecting said 6 stock holders, means includinga cam track and vertically movable cam rod coupled to said cross bar for supporting said stock holders in difierent positions of adjustment about their axis of tilting, pawl and ratchet means for imparting angular movement to each of said pins, means operable by reciprocatory movement of, said stock holders for actuating said pawl and ratchet means for imparting angular movement to said pins, and means for actuating said pawl and ratchet means upon displacement of said cam track to.

tilt said stock holders.

JAMES HALL. 

